1. Field of the Invention
The invention relates to a composition and method for consolidating aggregate (gravel, rocks, soil, sand, iron ore, wood chips, or other particulate solid material). More particularly, the invention relates to a composition including polyol, isocyanate, and ester, and a method for reacting the composition to form a polymer that consolidates aggregate together.
2. Description of the Related Art
As a result of the Alaskan hydrocarbon reserves, there is a significant amount of oil field related activities that occur on the Alaskan tundra. The Alaskan tundra typically comprises the following materials: salt water ice; fresh water ice; water or partly thawed ice; sand; gravel; bedrock; and cobble.
The tundra presents a number of problems for constructing or installing buildings, well heads, pipelines, drilling rigs, etc. As the permafrost freezes and thaws with changes in atmospheric conditions, the frozen tundra heaves, sinks and buckles. As a consequence, it is impractical to employ ordinary methods of building construction, as by erecting the building on poured concrete foundation walls, or on a poured concrete floor pad.
Additionally, as hydrocarbons flow upward in the well pipe toward a hydrocarbon well head, the warm hydrocarbons often melt the tundra's ice near the pipe. When the ice melts, the remaining gravel, rock, etc. simply falls to the nearest solid mass resulting in large caverns or sink holes around hydrocarbon wells. Additional gravel can be added to fill the holes, but continued melting can result in a continuing sink hole problem.
It has been known to inject a reacting composition into the ground underneath conventional slabs or floors. As discussed above, conventional slab construction cannot be used in environmental conditions such as the Alaskan tundra. U.S. Pat. No. 4,567,708 discloses a method wherein the components of an expanded polymeric foam, such as a closed cell polyurethane foam, are injected beneath the sunken or broken portion of an earth supported floor or slab. The space between the floor or slab and the earth is reached by drilling at least one hole through the floor or slab and injecting the components of the foam through the hole. As the foam expands between the earth and the floor or slab, a pressure is created, which forces the sunken or broken portion to rise. The hardened foam serves as a support for the previously sunken portion of slab or floor.
Another frequent construction issue occurring in many areas (not limited to the Alaskan tundra) is that temporary construction platforms, building foundations, or roads, etc. (collectively, surface bases) are often needed. The surface bases are frequently prepared by piling and compacting aggregate. One problem with using aggregate for surface bases is that there is little or no cohesiveness and the aggregate can become scattered decreasing the effectiveness of the base. To minimize this problem, some have applied heavy hydrocarbon products, etc. to the surface bases, but this can create numerous environmental problems.